OBSERVATIONS ON GIGANTIOPS DESTRUCTOR. 



195 



saltatory Orthoptera and is evidently to be interpreted as an ar- 

 rangement for the accommodation of a more voluminous and there- 

 fore more efficient extensor, or abductor muscle in the hind leg. 

 This morphological peculiarity, together with the leaping habit, 

 seem to me to be sufficient to justify a separation of these jumping 

 species from the remaining Myrmecias as a distinct subgenus, for 



FIG. 2. Femora in profile and cross section of five species of ants drawn 

 to the same scale, a. Gigantiops destructor; b, Coinponotus castaneus atner- 

 icanus Mayr ; c, Mynuccia nigrocincta Smith; d, small Myrmecia sanguined 

 Smith ; e, Harpegnathos saltator Jerdon. 



which the name Halmamyrmecia subgen. nov. (with pilositla 

 F. Smith as subgenotype) may be proposed. 



In Gigantiops I find an even more pronounced elongation and 

 basal incrassation of the hind femur than in Pristomyrmecia or 

 Halmamyrmecia. As there is only one species of Gigantiops, I 

 have compared its hind femur (Fig. 2a) with that of a non-leaping 

 Camponotus worker of the same size (&). It will be seen that 

 the difference in the length of the two femora is very pronounced, 



